Basic leucine zipper (bZIP) family in Asparagus (Asparagus officinalis): genome-wide identification, evolutionary, structure, collinearity, and expression analyses under abiotic stress at the seeding stage

Asparagus (Asparagus officinalis) is a crop with medicinal, horticultural, and nutritional uses. The basic leucine zipper (bZIP) family is a transcription factor family distributed throughout eukaryotes, including plants, and whose members participate in various biological processes, including plant growth, development, flowering, and stress responses. However, a few genome-wide studies of the bZIP family members have been reported. Here, 46 Asparagus bZIP members, named AobZIP01-AobZIP46, were identified from the reference genome via PFAM search and could be divided into 14 subgroups which were shown to be similar via motif and gene structure analysis. The molecular evolution, motif, and gene structure comparative analysis between A. officinalis and Arabidopsis indicated the accuracy of AobZIP member identification. Additionally, the cis-acting elements of the AobZIP members revealed that they might be associated with plant hormones and responses to abiotic stress. The collinear analysis predicted that the function of AobZIP members might be comparable to that of other species. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that AobZIP genes were enriched in the abscisic acid (ABA) pathway. Furthermore, the tissue-specific expression at the seedling stage revealed that root tissue could be used as a target tissue because of its high expression level. The expression of AobZIP genes determined by quantitative real-time PCR under abiotic stress at the seeding stage revealed that some AobZIP members could be candidate genes for plant breeding. This study offers insights for future research in improving the abiotic stress resistance of asparagus utilizing the AobZIP genes.